(P22-018-24) Protein Foods of Differing Sources and Processing Levels Have Minimal Impact on Weight and Lipid Outcomes

Objectives: Interest exists in examining health effects of protein foods based on source (e.g., plant versus animal) and processing (e.g., minimally versus ultra-processed). The objective of this study was to explore metabolic effects of dietary patterns characterized by different protein sources.

Methods: Participants were randomized in a pilot two-phase, three-arm trial to receive grass-fed, grass-finished beef; a commercially-available meat analogue; or legumes daily for 8 weeks. In Phase 1 (first 4 weeks), participants received meals plan with their assigned protein food serving as the sole protein source. For Phase 2, participants consumed the same quantity of the same protein foods, in addition to any other food desired, in any quantity desired. Data were collected at baseline, week 4, and week 8, including height/weight, blood lipids (i.e., total cholesterol, high-density lipoproteins (HDL) and low-density lipoproteins (LDL)), blood pressure, and skin carotenoids (Veggie Meter®). Data were analyzed using mixed repeated measures analysis of variance.

Results: Participants (n=30) were 43.3% male and 56.7% female, mean age=30.4 years, mean baseline body mass index=27.1 kg/m², (range=18.9-36.9 kg/m²). At week 8, retention was 100% in the beef and meat analogue groups, and 60% in the legume group. Results show no significant within- or between-subjects effects on weight, total cholesterol, HDL, LDL, blood pressure, or skin carotenoids. Trends show participants consuming legumes consistently lost weight at each time point, though this value only totaled -1.1% of initial weight, whereas those consuming beef gained weight at week 4 followed by a loss at week 8. Those consuming meat analogues remained stable. Participants consuming beef and legumes had a drop in their total cholesterol at week 4, which then increased at week 8, versus meat analogues, which remained stable. All groups had a decrease then subsequent increase in HDL.

Conclusions: Grass-fed/grass-finished beef, meat analogues, and legumes are largely interchangeable as dietary protein sources, though appropriateness may depend on individual baseline factors and goals (e.g., weight). These results need to be further explored in a larger, fully-powered clinical trial.

Funding Sources: Oklahoma State University seed funding